Fastener assembly

ABSTRACT

The present invention is a fastener assembly including a row of fasteners maintained in position by a carrier. The carrier includes a plurality of adjacent sleeves, each of which includes an upper breakable portion, a middle wall portion, and a lower breakable portion. When a fastener is driven into a work piece, the upper and middle portions of the fastener sleeve break away and the lower portion breaks into fragments, so that no residual sleeve parts remain with the fastener. This is accomplished by forming the carrier from a mixture of a stiff polyolefin material and a particulate filler to impart the necessary brittleness to the carrier sleeves. Also, the lower portion of the sleeve includes fragmentable tabs joined at wall junctions which are structurally weaker than the tabs, to facilitate fragmentation between the tabs.

FIELD OF THE INVENTION

This invention is an improved fastener assembly of the type wherefasteners such as nails are maintained in rows or strips useful in nailguns and other fastener driving tools. More particularly, the inventionis a fastener assembly which utilizes a novel carrier design and animproved carrier material for maintaining the fasteners in position.

BACKGROUND OF THE INVENTION

Fast-acting fastener driving tools are commonplace in the buildingindustry. Fasteners, such as nails or concrete or steel penetratingpins, are assembled in rows or strips that are adapted for use in thedriving tools. The strips are typically essentially flat so that thefasteners are maintained in position parallel to each other.

One way to maintain the fasteners in position is described in U.S. Pat.No. 5.069,340, issued to Ernst et al., the disclosure of which isincorporated by reference. As explained in the reference, a plurality ofcollated fasteners, each having a shank and a head, is maintained inparallel relationship using a carrier molded from a polymeric materialwhich can be polypropylene. The carrier includes a sleeve associatedwith each fastener.

A representative prior art fastener assembly is illustrated in FIG. 9,which shows a strip 10 of collated fasteners 12 (one of which is shown),held together by a carrier 30. Each fastener 12 is a drive pin, madefrom hardened steel, and is designed to be forcibly driven through awork piece, such as a galvanized steel channel or track, and into asubstrate which can be made of concrete or steel. Each fastener 12 hasan elongated shank 18 with a pointed end 20, and a head 22.

The polypropylene carrier 30 has a separate sleeve 32 for each fastener12. Each sleeve 32 includes a lower annular portion 34 and an upperbreakable portion 36 which is integral with the annular portion 34. Eachsleeve 32 grips the shank 18 of the associated fastener 12, with theannular portion 34 nearer to the pointed end 20 of the shank 18, andwith the breakable portion 36 nearer to the head 22.

In each sleeve 32, the breakable portion 36 has a pair of similar,laterally opposed, outwardly opening concave recesses 40 and 42. Betweeneach pair of sleeves 32, an upper bridge 46 and lower bridge 48 arelocated, which hold the adjacent sleeves together. During operation, theentire fastener assembly 10 is placed in the magazine portion of thepower driving tool. The power driving tool acts forcefully on the head22 of the first fastener 12, driving it downward. The force causes thebridges 44 and 46 to break between the first and second sleeves 32, sothat the first sleeve 32 separates from the carrier 30.

As the first fastener 12 is driven downward into an object, the upperbreakable portion 36 of the first sleeve 32 ruptures at the recesses 40and 42 and splits longitudinally into the two halves as the fastener 12enters the object. However, the splitting usually does not extend to thelower annular portion 34 of the sleeve 32, and the annular portion 34remains compressed between the head 22 of the fastener 12 and the objectinto which the fastener 12 is driven. Furthermore, the two halves of theupper (split) portion of the sleeve 32 usually remain integrallyconnected to the annular portion 34 and protrude outward from the objectas "tails". This is more fully described in U.S. Pat. No. 5,069,340, thedisclosure of which is incorporated herein by reference.

Because the surface into which the fasteners are driven is often hidden,the outward protrusion of "tails" does not present an aesthetic problemin many applications. However, there are some applications whereaesthetics are important, or where an outer coating or object is to beplaced directly on the substrate. These latter applications generate aneed or desire for fastener assemblies which do not generate outwardlyprotruding tails, or other residual fastener sleeve parts.

SUMMARY OF THE INVENTION

The present invention is a fastener assembly in which the carrier issufficiently strong and rigid to maintain the fasteners in position, yetin which the individual sleeves of the carrier will break in a mannerwhen the fastener is driven into an object so as not to leave outwardlyprotruding tails, or other residual sleeve parts. The invention includesboth a novel carrier design and an improved material composition for thecarrier.

The fastener assembly includes a row of collated fasteners held togetherin a strip by a carrier. Each fastener has a head portion and anelongated shank. The carrier includes a separate sleeve for eachfastener, and the adjacent sleeves are held together with bridges.

Each carrier sleeve includes an upper breakable portion and a lowerbreakable portion which is integral with the upper portion. The upperbreakable portion and lower breakable portion each extend completelyaround the circumference of the shank portion of the fastener. The upperbreakable portion also has a pair of similar, laterally opposed,outwardly opening concave recesses which facilitate splitting of theupper breakable portion when a driving force is applied to the head ofthe fastener, forcing the fastener into an object.

In order to facilitate the complete fragmentation of the fastener sleevewhen the upper portion is split, the upper portion and lower portion arejoined by a pair of middle sidewalls which, unlike the upper and lowerportions, do not extend completely around the circumference of the shankand which, at their narrowest points, cover less than two thirds of thecircumference of the shank. This design ensures that the middlesidewalls will be structurally weaker than the upper and lower portions,so that the walls will break more or less horizontally when the upperportion is split, before the lower portion fragments, as explainedbelow.

In order to facilitate subsequent fragmentation of the lower portion,the lower portion includes a plurality of laterally protruding tabsjoined by structurally weaker junctions. The tabs help align the lowerportion with the object into which the fastener is driven. When thefastener is driven into the object, the lower portion breaks apart atthe junctions between the tabs, so that no residual fastener is leftbehind at the point of entry of the fastener into the object.

In order to further ensure that the middle walls will break and notmerely bend, and the lower portion will fragment, the carrier is moldedfrom a rigid composition which comprises a stiff polyolefin mixed withabout 1-20% by weight of a particulate filler. The particulate fillercauses the already stiff polyolefin to become hard and brittle, so thatthe carrier walls will not substantially bend before breaking, and thelower portion will break rather than compress. By ensuring that thewalls will break, and the lower portion will fragment, the problem oftails and other residual fastener sleeve resulting from the driving ofthe fastener into an object is eliminated.

With the foregoing in mind, it is a feature and advantage of theinvention to provide a fastener assembly in which the upper portions ofthe carrier sleeves break away from the lower portions when thefasteners are driven into an object, and the lower portions then breakinto fragments.

It is also a feature and advantage of the invention to provide afastener assembly that is sufficiently durable and tough to keep thefasteners collated during shipping and handling, which allows thefasteners to be stripped off individually, and whose carrier sleeveswill disintegrate when the fasteners enter the workpiece.

It is also a feature and advantage of the invention to provide afastener assembly whose carrier is made from a stiff polyolefin mixedwith a particulate inorganic filler, causing the carrier to berelatively hard, brittle and inflexible.

The foregoing and other features and advantages will become furtherapparent from the following detailed description of the presentlypreferred embodiments, read in conjunction with the accompanyingdrawings. The detailed description and drawings are intended to beillustrative rather than limiting, the scope of the invention beingdefined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a fastener assembly of the invention, showingthe fasteners inside the carrier sleeves, and showing only fivefasteners and fastener sleeves for the sake of illustration. A typicalfastener assembly of the invention may contain 10 fasteners or morearranged in similar fashion.

FIG. 2 is a front sectional view of only the carrier component of thefastener assembly, without the fasteners.

FIG. 3 is a top plan view of the carrier component of the fastenerassembly.

FIG. 4 is a front view of the carrier component of the fastenerassembly.

FIG. 5 is a side sectional view taken along the line 5--5 in FIG. 4.

FIG. 6 is a side sectional view taken along the line 6--6 in FIG. 4.

FIG. 7 is a side view of the carrier shown in FIG. 4.

FIG. 8 is a bottom plan view of the carrier component of the fastenerassembly.

FIG. 9 is a perspective view of a prior art fastener assembly disclosedin U.S. Pat. No. 5,069,340, issued to Ernst et al.

FIG. 10 is a sectional view of the embodiments of a fastener assembly incombination with a magazine holder used for installation of thefasteners into an object.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Referring to FIG. 1, a fastener assembly, generally designated as 50,includes a row of hardened steel fasteners 60 held in parallelrelationship by a carrier 70. Each fastener 60 includes a head 62 and anelongated shank 64 with a pointed end 66. The carrier 70 is made of arigid filled polyolefin material as described below. The fastenerassembly 50 is used in the magazine of a power driving tool such as afast-acting nail gun. One example of a power driving tool is a TrakFast®tool, which is commonly used to connect steel channels or "tracks" toconcrete substrates, and for other construction applications. Thefastener assembly 50 may include 10-20 fasteners or more, arranged insubstantially parallel relationship as illustrated.

The carrier 70 includes a plurality of carrier sleeves 72, one forreceiving and surrounding the shank 64 of each fastener 60. Eachadjacent pair of carrier sleeves 72 is joined together by an upperbridge 52 and a lower bridge 54, which are integrally molded with thecarrier 70. As seen in FIGS. 1 and 4, the lower bridge 54 is preferablysmaller than the upper bridge 52. This helps to ensure that the bridge54 breaks more easily than the lower breakable portion of the fastenersleeve, as explained below.

The bridges 52 and 54 must be strong enough to hold the adjacent carriersleeves 72 together prior to and during loading into the power drivingtool, and during use in the magazine of the driving tool. In thisregard, the bridges must keep the row of sleeves 72 from bending,buckling, breaking or shearing during ordinary handling and use.However, the bridges 52 and 54 must readily shear when the drivingmechanism of the power tool applies a rapid downward force on the head62 of the leading fastener 60, causing the leading fastener 60 with itssleeve 72 to separate from the fastener assembly 50, so that the leadingfastener 60 can be driven into an object.

A certain balance must be considered when designing the size, shape,thickness and material of bridges 52 and 54. If the force required toshear the bridges is too low, the bridges may shear or break prematurelyduring handling and use of the fastener assembly 50. If the forcerequired to shear the bridges is unnecessarily high, then the energyrequirements for the power driving tool will increase, and its operationwill be slowed or the penetration of the fasteners in the substrate willbe reduced. Therefore, the bridges should be just strong enough tomaintain the sleeves 72 in position during normal handling and usebefore each leading fastener 60 is driven into an object.

Furthermore, the bridges 52 and 54 should not be so strong that theycannot be sheared without otherwise breaking the adjacent sleeves 72. Asshown in FIG. 4, for instance, it is especially preferred that theheight of the lower bridge 54 be less than the adjacent thickness of thesleeve 72 surrounding the fastener 60. As shown in FIGS. 3 and 8, thethickness of the bridges 52 and 54 should also be smaller than theadjacent thicknesses of the sleeves 72.

Each carrier sleeve 72 is preferably integrally formed and includes anupper breakable collar 74, a middle wall portion 76, and a lowerbreakable collar 78. As shown in FIG. 3, the upper breakable collar 74includes two halves 71 and 73 intersecting and joined at a pair ofsimilar, laterally opposed, outwardly opening concave recesses orindentations 51 and 53. The recesses 51 and 53 facilitate breakage ofthe top portion 72 as the fastener 60 is driven downward into a channelor track.

As shown in FIG. 3, the upper breakable collar 74 of the sleeve 72 has agenerally annular interior cross-section corresponding substantially tothe outer diameter of the shank 64 of the fastener 60, and an octagonalexterior cross-section which complements the interior dimensions of themagazine and which also facilitates proper breakage as explained below.The interior diameter of the upper breakable collar 74 (as well as ofthe lower breakable collar 78) of the sleeve 72 should be sufficient toslidably receive the shank 64 in a tight-fitting manner. The carrier 70is integrally manufactured (e.g. molded) separate from the fasteners,and it must be possible to insert the fasteners 60 into the sleeves 72without undue difficulty. On the other hand, the fit between fasteners60 and sleeves 72 should not be loose enough to permit the fasteners 60to fall out of the sleeves, or become misaligned. Preferably, the uppercollar 74 is longer and thicker than the lower collar 78, as illustratedin FIG. 2. This facilitates even and clean breakage of the sleeve 72during installation of a pin 60 into a substrate.

Referring to FIGS. 2 and 4-7, the middle portion 76 includes two walls61 and 63 which, unlike the upper collar 74 and lower collar 78, do notcompletely surround the shank 64 of the fastener 60. As shown in FIGS.5-7, the walls each have two concave rectangular boundaries (65, 66, 67and 68) defining rectangular openings 59 between the upper collar 74 andthe lower collar 78 of each sleeve 72. In the region of the rectangularopenings 59, the walls 61 and 63 cover less than two-thirds of the outercircumference of the fastener shank 64, preferably less than one-half,most preferably about one-third. As explained further below, theadvantage of having middle walls 61 and 63 which only partially surroundthe corresponding shank 64, is that this facilitates lateral breakage ofthe sleeve 72 when the upper collar 74 is split.

In the preferred embodiment shown in the drawings, the middle walls 61and 63 are the result of forming each carrier sleeve 72 with tworectangular center openings 59. The rectangular openings 59 preferablyhave sharp corners which create areas of high concentration of stress tofacilitate breakage when the pin enters the substrate. The middle walls61 and 63 are made even thinner by forming hexagonal openings 94 betweenadjacent sleeves 72, and between the upper and lower bridges 52 and 54.This saves material and further aids in the breakage of the sleeve 72when the fastener 60 is driven. Other methods for forming the middlewalls, and other configurations of the walls, are within the scope ofthis invention, as would be apparent to persons skilled in the art.

Referring to FIGS. 3 and 8, the lower breakable collar 78 of each sleeve72 has an annular interior cross-section which slidably grips thefastener shank 64 in the same fashion as the annular interior of theupper collar 74. The outer cross-section of the lower collar 78 isshaped like a cross, as shown in FIG. 8, due to the presence of fourfragmentable tabs 81, 83, 85 and 87. The tabs are preferably offset asshown in FIGS. 4 and 8, for instance, so that two of the tabs 83 and 87extend below the other two tabs 81 and 85. The offsetting of the tabsfacilitates moldability of the sleeve 72 during manufacture, andbreakage of the sleeve 72 during installation of the pin 60 into anobject. The tabs 81, 83, 85 and 87 constitute substantially the entirelower collar 78. As shown in FIG. 4, the fragmentable tabs have a heightor thickness extending from about the bottom of the lower collar 78 upto the lower boundary of the rectangular openings 59 which help definethe walls 61 and 63 of the middle portion 76. As shown in FIG. 8, thetabs are joined by a circular wall 91 which is structurally thinner andweaker than the tabs, so that the lower collar 78 fragments by breakingof the wall 91 when the fastener is driven into an object. The wall 91should be as thin as possible, to save material and facilitatebreakability, but thick enough that it remains intact when one pin isstripped from the strip by the driver blade.

In the preferred embodiment illustrated in FIG. 8, there are fourfragmentable tabs configured in the shape of a cross. Otherconfigurations for the lower portion 78 are also possible, and would beapparent to persons skilled in the art. For instance, there may be agreater or fewer number of fragmentable tabs, or the lower portion 78may have a different shape entirely. However, an important feature ofthe lower portion 78 is that, regardless of its configuration, itfragments and separates when the fastener 60 is driven into an object.

When the power driving tool injects a fastener 60 into an object, thebridges 52 and 54 between the leading carrier sleeve 72 and the nextadjacent sleeve are sheared as explained above with respect to thedrawings. Then, referring to FIGS. 1 and 2, as the fastener pin 60 isdriven into the object, the upper collar 74 of the sleeve 72 willfragment and break away due to separation of the recesses 51 and 53. Asthe fastener pin 60 further penetrates the object, the lower collar 78will fragment and break away as the tabs 81, 83, 85 and 87 fragment andseparate due to breakage of the wall 91.

The fastener 60 continues to penetrate the object until the head 62becomes firmly engaged against the upper surface of the object. Theoutward force exerted by the fastener head 62 as it passes through thesleeve 72, causes complete fragmentation and scattering of the sleeve 72so that no portion of the sleeve enters the object with the fastener, orremains wedged between the object and the fastener head.

As illustrated in FIG. 1, it is preferred that a distance be maintainedbetween the head portion 62 of the fastener 60 and the upper collar 74of the sleeve 72, prior to installation of the fastener 60 into anobject. This distance may be at least about 0.105 inches for a pinhaving a length of about 0.75 inches or longer, and may be at leastabout 0.60 inches for a pin having a length of about 0.50 inches to lessthan about 0.75 inches. The purpose for maximizing this length is tominimize the distance between the head portion 62 of the fastener 60 andthe top wall of a magazine holder which carries the pins prior toinstallation.

FIG. 10 shows, in cross-section, two embodiments of a fastener assembly50 carried inside a magazine holder 210 of a typical fastener drivingtool. As the individual fasteners are used, the fastener assembly passesfrom right to left in the magazine holder 210. The pins are separatedone by one using a piston driver blade (not shown) and are passedthrough a bore 220 into an object below. As shown in the right hand sideof FIG. 10, especially when firing the next-to-last pin of any strip,the fastener assembly 50 may become angled or "cocked," causinginterference with the installation process, if the distance between thehead 62 of the pin and the inner wall 212 at the top of the magazineholder 210 (also known as the shear block) is too large. As shown in theleft hand side of FIG. 10, the angling problem can be reduced oreliminated by minimizing the distance between the head portion 62 of thefastener 60 and the top inner wall 212 of the magazine holder 210.Suitably, this distance should be less than about 0.010 inches,preferably less than about 0.008 inches, more preferably less than about0.005 inches.

In order to ensure that sleeve 72 will fragment and break away asintended, so as not to leave tails, the proper selection of a materialfor molding the carrier 70 is an important aspect of the invention. Thecarrier must be composed of a material that is relatively hard andbrittle, and which has a greater tendency to fracture and break than tobend when subjected to a driving force. Yet, as explained above, thecarrier material must also be strong enough to maintain the integrity ofthe nail assembly 50 during normal handling and use, and must be able tobe separated by the driver blade in the magazine.

The inventors have learned that the foregoing properties can be obtainedby combining a stiff polyolefin material with a particulate filler, andblending them together to form a substantially homogeneous mixture. Thestiff polyolefin should have a density greater than about 0.900grams/cm³, preferably greater than about 0.925 grams/cm³, morepreferably greater than about 0.945 grams/cm³. Stiff polyolefinmaterials include high density polyethylene (i.e. having a density of0.945 g/cc or greater), medium density polyethylene (i.e. having adensity of 0.925-0.945 g/cc), linear low density polyethylene (i.e.linear copolymers of ethylene with up to 10% by weight of analpha-olefin having 3-12 carbon atoms and having a density of0.910-0.925 g/cc), and combinations thereof. Of these, the mostpreferred stiff polyolefin is high density polyethylene.

Particulate fillers can be inorganic or organic and include, but are notlimited to, talc, alumina, graphite, clay powder, glass spheres, silica,titania, wood flour, calcium carbonate, polytetrafluoroethylene powder,barium sulfate, and mixtures including one or more of these. Talc powderis the presently preferred filler. Talc generally has the chemicalformula Mg₃ Si₄ O₁₀ (OH)₂. The particulate filler can constitute about1.25% by weight of the total carrier composition (polyolefin mixed withfiller), preferably about 3-10% by weight, more preferably about 4-7% byweight. In a presently preferred embodiment, the carrier compositioncomprises about 5% by weight talc and about 95% by weight high densitypolyethylene. Higher filler loads generally cause increased brittlenessand ease of fracturing. If the amount of filler is too low, the sleeveis difficult to fracture and will often not separate from the fastenerpin during installation.

The particle size of the filler is not especially important, providedthat the proper balance of strength, brittleness and breakability of thecarrier can be achieved. Generally, the filler will have an averageparticle diameter of about 0.1-250 microns, more commonly about 10-150microns. In one embodiment, talc filler is present in the form ofparticles of masterbatch consisting of 80% talc and 20% polypropylene,the particles having an average diameter of about 100 microns. Thecarrier 70 is typically manufactured using a molding process, such as aninjection molding process. A wide variety of filler sizes and types canbe employed with polyolefins in these molding processes.

While the embodiments of the invention described herein are presentlyconsidered to be preferred, various modifications and improvements canbe made without departing from the spirit and scope of the invention.The scope of the invention is indicated in the appended claims, andchanges that fall within the meaning and range of equivalency areintended to be embraced therein.

We claim:
 1. A fastener assembly, comprising:a plurality of fastenersarranged in a row; and a carrier including a plurality of connectedcarrier sleeves for maintaining the fasteners in position; wherein thecarrier comprises a mixture including a polyolefin material having adensity greater than about 0.900 grams/cm³, and a particulate filler. 2.The fastener assembly of claim 1, wherein the polyolefin materialcomprises a polyolefin selected from the group consisting of highdensity polyethylene, medium density polyethylene, linear low densitypolyethylene, and combinations thereof.
 3. The fastener assembly ofclaim 1, wherein the polyolefin material comprises high densitypolyethylene.
 4. The fastener assembly of claim 1, wherein thepolyolefin material has a density greater than about 0.925 grams/cm³. 5.The fastener assembly of claim 1, wherein the polyolefin material has adensity greater than about 0.945 grams/cm³.
 6. The fastener assembly ofclaim 1, wherein the particulate filler constitutes about 1-25% byweight of the carrier.
 7. The fastener assembly of claim 1, wherein theparticulate filler constitutes about 3-10% by weight of the carrier. 8.The fastener assembly of claim 1, wherein the particulate fillerconstitutes about 4-7% by weight of the carrier.
 9. The fastenerassembly of claim 1, wherein the particulate filler comprises a materialselected from the group consisting of talc, alumina, graphite, clay,glass, silica, titania, wood flour, calcium carbonate,polytetrafluoroethylene, barium sulfate, and mixtures thereof.
 10. Thefastener assembly of claim 1, wherein the filler comprises talc.
 11. Thefastener assembly of claim 3, wherein the filler comprises talc.
 12. Afastener assembly, comprising:a plurality of fasteners arranged in arow, each fastener including a head and an elongated shank; and acarrier including a plurality of connected carrier sleeves receiving andsurrounding a portion of each fastener; wherein the carrier includes afilled polyolefin material; and each of the carrier sleeves includes anupper breakable collar, a middle wall portion and a lower breakablecollar.
 13. The fastener assembly of claim 12, wherein the upperbreakable collar comprises two recesses for facilitating breakage. 14.The fastener assembly of claim 12, wherein the upper breakable collarcomprises a generally annular interior cross-section correspondingsubstantially to an outer diameter of the elongated shank of a fastener.15. The fastener assembly of claim 12, wherein the upper breakablecollar is longer and thicker than the lower breakable collar.
 16. Thefastener assembly of claim 12, wherein the middle wall portion comprisestwo walls.
 17. The fastener assembly of claim 15, wherein the wallsdefine rectangular openings therebetween and with the upper and lowercollars.
 18. The fastener assembly of claim 15, wherein the walls in themiddle wall portion cover less than about two-thirds of an outercircumference of a fastener shank.
 19. The fastener assembly of claim18, wherein the walls in the middle wall portion cover less than aboutone-half of the outer circumference of the fastener shank at thenarrowest region.
 20. The fastener assembly of claim 12, wherein thelower breakable collar comprises a generally annular interiorcross-section corresponding substantially to an outer diameter of theelongated shank of a fastener.
 21. The fastener assembly of claim 12,wherein the lower breakable collar comprises a plurality of fragmentabletabs joined to a wall which is structurally thinner and weaker than thetabs.
 22. The fastener assembly of claim 21, comprising four of the tabsarranged in a cross.
 23. The fastener assembly of claim 22, wherein twoof the tabs are offset relative to the other two tabs.
 24. The fastenerassembly of claim 12, wherein the carrier further comprises bridgesbetween adjacent carrier sleeves.
 25. The fastener assembly of claim 24,wherein the carrier comprises an upper bridge and a lower bridge havingan opening between them.
 26. The fastener assembly of claim 25, whereinthe opening is hexagonal.
 27. A fastener assembly, comprising:aplurality of fasteners arranged adjacent to one another, each fastenerincluding a head and an elongated shank; and a carrier including aplurality of adjacent connected carrier sleeves for holding thefasteners; wherein each carrier sleeve includes an upper breakablecollar, a middle wall portion, and a lower breakable collar including aplurality of laterally extending fragmentable tabs; wherein the lowerbridges are smaller than the upper bridges.
 28. The fastener assembly ofclaim 27, wherein the lower portion comprises four of the laterallyextending tabs, and a breakable wall joined to the tabs.
 29. Thefastener assembly of claim 28, wherein the four tabs are arranged in across, and the breakable wall is circular.
 30. The fastener assembly ofclaim 27, wherein the adjacent carrier sleeves are connected using upperand lower bridges.
 31. A fastener assembly, comprising:a plurality offasteners arranged adjacent to one another, each fastener including ahead and an elongated shank; and a carrier including a plurality ofadjacent connected carrier sleeves for holding the fasteners; whereineach carrier sleeve includes an upper breakable collar, a middle wallportion, and a lower breakable collar including a plurality of laterallyextending fragmentable tabs; wherein the lower portion comprises four ofthe laterally extending tabs, and a breakable wall joined to the tabs.32. The fastener assembly of claim 31, wherein the four tabs arearranged in a cross, and the breakable wall is circular.
 33. Acombination comprising a fastener assembly and a magazine holder;thefastener assembly including a plurality of fasteners arranged in a row,and a carrier including a plurality of connected carrier sleeves formaintaining the fasteners in position; the carrier including a mixtureincluding a polyolefin material having a density greater than about0.900 grams/cm³, and a particulate filler; the magazine holder includingan upper internal wall; wherein the distance between the head of atleast one fastener and the upper internal wall is less than about 0.010inch.
 34. The combination of claim 33, wherein said distance is lessthan about 0.008 inch.
 35. The combination of claim 33, wherein saiddistance is less than about 0.005 inch.